SPARK KNOCK ?

[HUNTED]

Alright here is the scoop i had a 94 mustang that we built a aluminum headed motor for it and it ran great in that car. We had it all tuned and nothing was a problem. Well i got this wild urge to build an older coupe. So I pulled the motor and swapped them out. There is a couple things different in the two motors such as the distributer, the throttle body and spacer, and some headers, nothing else has change as far as internally in the motor. We can drive the car all around town and have no spark knock issues as soon as you hit wide open throttle it begins to ping like a botch!!! If anyone has had similar problems as this please feel free to chime in and help out and dont be afraid to ask any ? if i have left something out?



Thanks alot
Kurt

 

[dragnazz5.0]

dont know what to tell you except that the computers from 94 are different from earlier models. they have different timing curves set which could be the problem. im trying to figure out a way to build an add on knock sensor for our cars that will help out with this, but it will probably be a while before its working.

 

[HUNTED]

yes i realize that BUT i in my 94 car i had it repinned to a a9l processor

 

[jrichker]

You are probably running lean at WOT due to some differences in airflow through the MAF. In place of a custom tune, try cranking up the fuel pressure or clocking the MAF.

Dump the codes and see what the computer says is wrong. This will help spot any problems with the sensors or wiring.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $35.

 

[HUNTED]

A/R RATIO IS GOOD SO THAT IS OUT WE HAD IT ON A DYNO TRING TO CUSTOM TUNE IT. AND AS FAR AS CODES THERE IS NO CHECK ENGINE LIGHT

 

[HISSIN50]

In the new car, did you upgrade the fuel pump, do a fuel filter, etc?

good luck.

 

[vristang]

The lack of CEL does not mean that the computer is not throwing codes.
You still need to check them.

I am confused as to what computer and MAF you are using.
Can you clarify?

You can put all of this stuff in your sig, then you don't have to provide that info for each thread/post you make.


jason